Removes hardcoded cookbooks in favor of a git submodule

Since the Vagrantfile is now inside the chef-ckan directoy, you
should set VAGRANT_CWD='chef-ckan' to make 'vagrant up' work.

For more details check:
https://github.com/CodeandoMexico/ckan/wiki/Adding-chef-ckan
Using wilhelmbot's hacked recipes
Merge pull request #4 from CodeandoMexico/chef-submodule

Chef submodule